Field of the Invention
The present invention relates to an image recording apparatus and an imaging apparatus. More particularly, the present invention relates to an image recording apparatus and an imaging apparatus that record surrounding images such as omnidirectional images.
Description of the Related Art
An omnidirectional image is an image that is captured as one continuous image over a range of 360 degrees orthogonal to a front direction, and is captured, for example, by a dedicated omnidirectional camera or by an ordinary camera with an omnidirectional imaging unit attached thereto. For example, an image that covers an entire range of 360 degrees on a horizontal plane within its view angle can be obtained. An omnidirectional imaging unit is, for example, an adaptor attachable to and detachable from a front surface of an imaging lens of an ordinary camera, and has a structure that includes a circular conical mirror surface that is protruded toward the imaging lens. The circular conical mirror shape deflects the optical axis of the imaging lens into a lateral direction.
An omnidirectional image captured by using such an omnidirectional imaging unit generally has a donut shape whose central and peripheral portions have different scales as illustrated in FIG. 7A. This image is very hard for a user to visually recognize. Therefore, usually, this captured image is digitally processed by a personal computer or the like so as to be developed into a panoramic image covering an entire circumference as shown FIG. 7B. Hereinafter, such a process of converting an omnidirectional image into a panoramic image will be termed panoramic development. Japanese Patent Application Laid-Open No. 2005-303340 describes that an omnidirectional image is converted into images of an ordinary view angle by a non-linear resolution conversion process.
Furthermore, a picture covering an entire 360-degree area can also be captured by one shot through the use of a super-wide-angle lens such as a fish-eye lens. In this case, the captured image has a circular shape whose central portion corresponds to a front area.